


Quod Erat Demonstrandum

by Blue_Night



Category: Men's Football RPF, Real Person Fiction
Genre: Anal Fingering, Anal Sex, Challenges, Enemies to Lovers, Explicit Sexual Content, Fanfic of Fanfic, First Time, Hate Sex, M/M, Sex Research, so many suppressed feelings
Language: English
Status: Completed
Published: 2019-01-30
Updated: 2019-01-30
Packaged: 2019-10-19 14:45:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,906
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17603324
Author URL: https://archiveofourown.org/users/Blue_Night/pseuds/Blue_Night
Summary: quod erat demonstrandum, Latin quote:which was to be proven. A term usually used for mathematical proof, but there are other things that need to be proven as well sometimes.Like in when Bernd challenges Marc on his skills as a lover - and Marc is determined to prove him wrong.





	Quod Erat Demonstrandum

**Author's Note:**

  * For [Khalehla](https://archiveofourown.org/users/Khalehla/gifts).
  * Inspired by [Turn the lights down low](https://archiveofourown.org/works/8204710) by [Khalehla](https://archiveofourown.org/users/Khalehla/pseuds/Khalehla). 



> Dear Khalehla,  
> I hope that I delivered well. Thank you for letting me play in your universe as well, this here was so much fun to write! (I even might have blushed a few times while writing this... :-P)
> 
> This fic is based on the talk Marc and Bernd have in chapter three of Khalehla's awesome work _'Turn the lights down low'_ , where Marc tells Bernd that he'd done research about how to sleep with another man before their first time - because Bernd had insulted him about his skills as a lover. There are lines Bernd is saying and Marc is thinking in this fic that Khalehla kindly shared with me, this fic is entirely wrapped up around these lines to make Marc and Bernd's first time fitting into their wonderful universe. Everything happening here belongs to Khalehla's world, I'm just visiting it with their kind permission. <33

Marc leans back in his chair and rubs his eyes, frowning thoughtfully at his laptop. This is much more difficult than he thought it to be, but he's going to pull that through, no matter what. If Bernd is going to question his skills, then Marc is going to prove him wrong. (Something Bernd Leno should actually know at this point, but well, sometimes that man is really slow on the uptake.)

He still remembers the morning Bernd challenged him clearly, and this even though he was still slightly hungover after the night out with their teammates. Marc had been up before Bernd, (yeah, the coaches still think that rooming them together will eventually lead to him and Bernd becoming friends – as if this is ever going to happen, really!), and he'd picked up on the opportunity to take a long shower – like in really long – just to annoy Bernd. When he finally emerged from the bathroom again, Bernd was sitting in his bed, still ruffled and sleepy, glaring at him despite the fact that his red-rimmed eyes diminished the effect.

 

***

 

 _“Finally!” Bernd snaps at him, clearly pissed off. “Was about time. Put your phone on silent the next time, there were at least twenty messages and five calls from your_ girlfriend _.” Marc narrows his eyes at the way Bernd is emphasizing the word 'girlfriend', just as if it was quite shocking that Marc even has one. He leans against the closed bathroom door with his arms folded across his chest, staring back down at his rival._

_“Do you have any problem with my girlfriend?” he asks, pulling a mocking snort from his counterpart. “Only when she's trying to reach you that early while you asshole are using up all of the hot water.”_

_“You should get up before me the next time, then,” Marc suggests smugly, and Bernd's glaring becomes even more intensive, probably because he's angry that Marc doesn't suffer as much from the alcohol as he's obviously still doing._

_“It's actually amazing that you even have a girlfriend, ter Stegen. Whatever it is she's seeing in you, it can't be your amazing skills as a lover.” Bernd clearly only wants to insult him to win the upper hand again, but his words sting nonetheless. Marc takes a deep breath, clenching his fists against his chest because the temptation to wipe that sneer from Bernd fucking Leno's face is almost too strong to resist it._

_“I didn't hear you complain about my 'skills as a lover' last night, Leno,” he sneers back, pulling another scornful snort from the other man. They might hate each other, but both of them know that actually fighting with one another until at least one of them gets a black eye is not really an option if they ever want to be called up for the A National Team again, and having hate sex with Bernd is almost as good as hitting him would be, and definitely more pleasurable._

_They were still bitching when they came back to their room, just like they had done the entire evening, but the minute they lay in their king-size bed, they were all over each other, snarling, kissing fiercely and jerking each other off until they fell asleep with their hands still wrapped around each other's dicks, too tired to clean up the mess they'd made. Therefore the long shower this morning. (And no, Marc will not admit that he was wishing that Bernd would shower together with him, not even if someone pointed a gun at him, really not. He still has his pride after all.)_

_“Bah, you didn't prove anything, ter Stegen. That was only a hand job. You're a guy with a dick, it's easy to jerk another dude off when you're one yourself. That's why I can't believe that you're able to make a girl happy. Girls don't have dicks, and your lack of imagination and empathy must make it hard for you to keep her satisfied. Sleeping with someone is a little bit different from jerking them off actually is, you can't deny that. It would need real skills you don't possess.”_

_“It will be my pleasure to prove my_ 'skills' _to you the next time we're called up then, Leno!” Marc growls, but Bernd only laughs at him. “Don't make a fucking fool of yourself, ter Stegen. Hell, you couldn't even figure out how to make me feel good if I gave you an instruction manual filled with diagrams.”_

_Bang!!_

_Marc feels his mouth drop open, and he finds himself staring at Bernd in both anger and disbelief at_ that _challenge. He's so going to teach that asshole that he's wrong, and if it'll be the last thing he's doing in this life._

 _He quickly snaps his mouth shut again, curling his lips into a gleeful smile._ 'Fuck, I'm gonna give you the best orgasm of your life, Leno, don't you doubt that!' _he thinks to himself, because he's not the man to back away from such a challenge, never._

_“We'll see, Leno, we'll see,” is all he says, though, pushing himself away from the door to stalk over to the bed and take his smartphone when it starts to beep with another message again. He can feel Bernd's eyes on his face, but he ignores him deliberately, grinning to himself and already making plans for their next meeting when they're called up together again while he busies himself with his phone._

_Bernd should really know better than to furnish him such a fit occasion, and Marc will teach him a lesson that asshole will never forget, that much is sure._

 

***

 

That's why he's sitting here with his laptop in the middle of the night, doing his research to make sure that Bernd will never ever question his skills as a lover again when Marc is done with him. The act itself is not so different from what Marc already knows from his experiences with girls, but there are things he needs to think about and be careful of, and Marc knows that he will have only this one chance to prove to Bernd that he's the best at everything – may it be football and being a goalie, or him knowing how to turn another man into a panting and quivering mess with his fucking skills.

Marc yawns heartfeltedly before he goes back to reading what is written on that special page he's found, rubbing his hands in anticipation and a huge smile spreading out on his face.

“You'll be so screwed when I'm done with you, Bernd Leno, so screwed, you don't even know how fucked and screwed you'll be!”

 

***

 

Marc usually hopes that Löw and Köpke will finally notice that rooming him together with Bernd is generally a bad idea and won't lead to them become best buddies at the end of the day, but just serve to make them hate each other even more, but this time he finds himself murmuring silent prayers that they won't break from the usual tradition this time of all times; because it will be much easier for Marc to teach Leno a lesson he hopefully won't forget again when he doesn't have to sneak into Bernd's room in the middle of the night.

Luck is on his side, and Marc has a hard time keeping the gleeful smirk of anticipation and schadenfreude inside for the rest of the day.

 

***

 

“Don't forget to put your phone on silent today!” Bernd demands when they're back in their hotel room after a first light training, dinner and hanging out together with Julian, Joshua, Manu and Thomas for a while.

Marc is glad that Bernd wanted to call it an early night as well, and Bernd's furtive looks in his direction during the whole day hadn't been lost on him, something that would normally annoy him pretty much, but which he was more happy about this time than he cares to admit.

“No worries, I know that men of your age need their beauty sleep,” Marc flutes, fluttering his eyelashes as he grins with faked sympathy written all over his 'innocent' face.

Bernd is gaping at him incredulously before he's finally pulled himself together again, but the moment is gone before he could come up with a witty reply, and so he simply resorts to stalking over to the bathroom and pointedly locking the door right before Marc's nose. Marc just shrugs and takes his toilet bag to knock at Julian and Joshua's door to ask if he can use their bathroom for brushing his teeth.

Marc is already lying comfortably in his bed when Bernd comes out of the bath again, and he's made sure at least three times that the items he will hopefully need later that night are safely stuffed in the drawer of his nightstand. He has a hard time keeping his gaze from darting to the drawer again when he feels Bernd's eyes on him, and he continues to ignore him, pretending to read something interesting on his phone because he knows that Bernds hates it when he ignores him. Their fucked up hate-fuck-enemies-relationship draws them together like a moth is drawn to the light that will burn it, and it doesn't take long until the mattress beside him shifts and Bernd pulls the phone out of his hand with a snarl to get his attention.

They haven't seen each other for months – (enough time for Marc to do some very thorough and careful research, but that's nothing he will tell Bernd, of course) – and Marc is grateful that he doesn't need to trick Bernd into a fight that will eventually and inevitably lead to rough sex tonight.

The tension between them is so thick that Marc could cut it with a knife, has been thick and heavy with hormones of anger and sex for hours. Bernd is literally buzzing with all the emotions that need a valve: fury, hate, rivalry, hurt and – heated and fierce desire for each other neither of them can deny. Giving in to their desire isn't easy for either of them, but it's the simple truth that they can hardly keep their hands off each other when they're alone, and it's Bernd as much as it is Marc who's seeking touch and closeness.

“So eager to enjoy my poor skills as a lover?” Marc breaks the heavy and anger-filled silence between them at last – after letting the tension build even higher for a few very long seconds, of course – and he lets out a yelp when Bernd is all over him with another growl, his rough kiss more a punishment and an attack than a real kiss.

Marc surrenders to the kiss for a moment, and when Bernd is thriving on his victory, thinking that he has Marc exactly where he wants him to be, he makes a sudden move and traps Bernd right underneath him, pinning him down and sucking the air out of his lungs when he takes over control of their kiss. Bernd is too stunned to react, and Marc uses his shock to strip his shorts down to his knees and wrap his hand around Bernd's half-hard cock. He needs him hard and aching for doing what he wants to do, and Marc knows from experience that giving Bernd time to think is not a clever idea if he doesn't want his lesson to be in vain. He uses all of his knowledge to get Bernd rock-hard in record time, never breaking their angry kiss and teasing the sensitive head of Bernd's pretty dick, (yes, that man has a beautiful dick, long and thick and perfect, but Marc won't tell him that, because Bernd's already far too smug and conceited for his own good anyway), until the furious man pinned down beneath him shivers violently, trying to get his own hands on him.

Marc bats his hand away and moves from his bruised lips to his earlobe to bite into it, and Bernd goes still, his ragged breathing his only motions now. Marc nibbles and sucks at his ear and his throat until Bernd lets out a loud moan, and he finally raises his head to look down at his counterpart.

Bernd is staring back at him, his pupils so dilated that the blue of his irises is not visible any longer, and his jaw is working, but he neither tries to push Marc off, nor does he make any attempt to take over control again. Marc allows himself a deep breath before he bends down to kiss Bernd again, this time more gentle and careful, and Bernd makes a small noise and kisses him back, unconsciously arching into the touch of Marc's hand to get more friction.

Marc kisses and strokes him until he can feel Bernd getting close, enjoying the feeling of hard muscles under deliciously smooth skin far too much for his peace of mind. He needs to stay focused and pull his mission through, and he goes back to kissing Bernd's neck and sucks a nice bruise into his collarbone before he finally dares to nudge him around until Bernd is lying on his stomach. The latter tenses up and yelps a bit, but Marc pushes his tee up and places teasing bites on his back and his shoulders while reaching for the drawer to take the lube and the condoms out of it. Bernd turns his head on the pillow to search for Marc's gaze, and Marc locks eyes with him, lube and condoms in his hand.

When Bernd doesn't move, just looks at him, Marc brushes a kiss against his lips and his jaw, opening the bottle to line his fingers up. He pushes them between Bernd's spread legs, and he's nervous like hell, but he doesn't show it as he pulls at Bernd's shorts to get them off, now that he's sure that Bernd won't fight against him. His counterpart is even trying to make it easier for him, wriggling his backside to push his underwear down, and fuck has this man a gorgeous ass. Marc wants to worship these perfectly rounded cheeks with his hands and his mouth, but he's on a mission here, and there's really no need to get pathetic and lunatic over Bernd Leno's glorious butt just because he'll finally, finally get to fuck him.

Bernd embraces his pillow and buries his face in it to muffle his groans when Marc decides that it is about time to put the long nights of thorough research to good use, stroking along the cleft of the most beautiful ass he's ever seen, reaching deeper and deeper until he can circle the puckered hole, and his breath catches in his throat. Woah, this feels, it feels... definitely better than Marc expected it to feel, and if Bernd's gasp is any indication, then he likes Marc's finger on his hole pretty much, too.

The muscle is still too tight to push in, though, and Marc recalls the things he'd read weeks ago in his mind, circling and massaging and stroking the tight rim until Bernd is wriggling again, apparently craving to feel Marc's finger inside him as urgently as Marc wants to put it there himself.

It's warm and tight and – holy shit – Marc is hot and maddeningly hard just from pushing his finger into Bernd Leno's virgin hole. (Marc at least assumes that Bernd is still a virgin when it comes to being fucked by another man, and if he's not, then Marc will make sure that Bernd will forget every other dude he'd let fuck him before that night.)

“Fuck!” Bernd groans into the pillow, “oh, fuck!” Marc chokes out when he starts to move his finger back and forth. He needs several minutes to work up the courage and reach deeper than to just the first knuckle, but he clearly remembers the instructions how important stimulating a man's prostate is, and he starts to search for this special knob when he dares to push deeper because Bernd doesn't complain or tries to pull away, but moves his hips along in time to Marc's clumsy poking.

It's probably only because Bernd is aching to get some friction on his neglected cock, but his writhing has the desired effect, because he suddenly arches up with a strangled shout, a heavy shudder wrecking the other man from head to toe. Ah, he's found it! Marc reaches for this spot again, stroking it eagerly, and he can hardly bite back the triumphant growl that wants to escape him when Bernd starts to moan and gasp, arching and pushing back against him ever so nicely.

This is going better than Marc could have hoped for, and he inwardly praises himself for his thorough research, thriving on Bernd's reaction more and more. His poor cock is screaming to finally be allowed to explore this heavenly place as well, but Marc always strives for perfection, and the instructions made clear that a proper preparation is crucial for the first time, so he adds a second and then a third finger to make sure that Bernd will never question his skills as a lover again.

Time goes by in a blur of gasps and moans and shivers from both Bernd and Marc, and Marc almost tears his shirt and his shorts in his haste to get rid of them when he's sure that Bernd is more than ready for the next step, the tension in his shoulders an unmistakable sign that he's pretty close to lose it. But not before Marc is buried balls-deep inside him. If Bernd is going to come tonight with the best orgasm he's ever had, then he will come from Marc's cock fucking him into the mattress.

“What are you waiting for, ter Stegen?” Bernd groans when Marc takes a second to admire Bernd's beautiful ass once more, glad that the other man can't see his face from his position – as his expression is surely a stupid mixture of pure want and foolish adoration. But hell, this gorgeous ass! And it's all Marc's tonight. (And Marc will be damned if he won't make sure that it will stay his ass in the foreseeable future at least!)

Okay, Bernd is getting annoyed, eventually running out of patience and glaring at Marc over his shoulder, so he'd better hurry up and get the real party started. His fingers tremble when he puts the rubber over his aching and leaking cock and lines it up, his balls already starting to turn blue after all the tension and frustration of not being allowed to empty themselves for so long, but his own patience will be rewarded soon, only a little while longer, until he's turned Bernd Leno into a sex-wrecked panting mess.

Marc covers Bernd with his own body, pushing his legs further apart, and Bernd braces his weight onto his bent forearms in order not to choke, exposing his neck to Marc's hungry stare. Bernd owns not only a glorious ass and a pretty dick, but also a beautiful swan-like neck, and Marc takes advantage of Bernd's trapped position and bites him playfully on all the spots within his lips' reach. It pulls more moans and shudders from his prey, and Marc knows that Bernd's dick is throbbing and leaking desperately against the sheets when he slowly and nervously searches his way into his body with his own cock for the very first time.

Fuck, fuck, fuck, boah!! Tight, so tight and so hot, how is he supposed to hold back until Bernd is begging him to make him come? This was not part of his research, and Marc chides himself that he wasn't prepared for this. He should have known that Bernd would catch him off guard and by surprise, even though Marc is the one in charge and on top. But all their fights and contests have taught Marc a lot of lessons as well over the past years; and one of them is how to keep his self-control despite the storm of feelings raging inside Marc every time Bernd is testing his limits, so he will just rely on his former experiences and focus on riling Bernd up until he crumbles first – like Bernd's doing most of the times when Marc just pushes the right buttons. (Which he has reached true mastery in, really!)

“Uuuh!” Bernd draws air through his gritted teeth, and Marc stops pushing in, humming soothingly into his ear and rubbing comforting circles over his flanks. Bernd's skin is hot and damp with sweat, and Marc could drown in his scent, his natural fragrance having become so familiar and consoling a long time ago, but Marc realizes it only in this special moment. He pushes his nose against Bernd's nape to inhale the alluring mixture of sweat, male hormones, shower gel and Bernd, just Bernd, and when the other man relaxes underneath him, he carefully pushes all the way in, biting back the curse that almost slips from his lips.

They lie there for a moment, their harsh breathing the only sounds audible, and Marc feels goosebumps forming on his entire body, his toes curling at how fucking good this feels. Bernd's hot walls clench around his throbbing cock in all the best ways possible, and Marc instinctively closes his lips around Bernd's shoulder and bites the soft flesh that tastes as wonderfully as it smells.

_Mineminemineminemine!!!!!!!!!!_

_'Mine, all mine, minemineminemine!!!'_ is all Marc can think when he can't fight the urge to move any longer, pulling all the way out and pushing back in to the hilt right away again. Bernd shouts into the cushion he's clenching his jaw around, and Marc can see him clutching the sheets as if his life depended on it. There are goosebumps on Bernd's arms and his back as well, and Marc can feel Bernd's toes curling too because of his position pressed closes against the other man from the shoulders down to their feet. He repeats his movements several times, and when Bernd tries to move against him, Marc luckily remembers that instruction about the right angle and shifts his weight, trapping Bernd's legs between his own and wriggling until he can push even deeper to reach Bernd's prostate again.

Bernd almost pushes him off with the first hit that finds its aim, and Marc needs to reposition himself, but then they find a good rhythm soon, and the noises he can pull from the other blond are just sooooo beautiful. Marc nuzzles Bernd's damp hair and teases his earlobe with playful bites before he goes back to nipping and sucking at his shoulders and his throat, and he can't remember a single time he's been as hard as he is now, so hard that he will go crazy if he can't shoot his load like in _now_!

As much as Marc would love to make Bernd come from his cock only, but well, there must be room left for some improvement for the next times they will do this, and Marc also aches to feel the evidence of Bernd's best orgasm ever spilling all over his fingers – just to make sure that he's taught his rival his lesson well, of course. Not because he loves the heavy weight of Bernd's aroused dick in his hand, or because there's always this strange ache in his chest when Bernd comes apart because Marc was the one who has made him fall apart...

Only to make sure that his mission was successful, there's really no other reason for Marc wanting to jerk Bernd off so very badly. Bernd _whimpers!_ when Marc reaches around his midsection, never faltering in his steady thrusts, and it threatens to make him come right on the spot. Who would have thought that Bernd Leno is capable of such sounds? Marc runs his fingers over the whole length of Bernd's twitching erection before he circles the wet tip with his thumb several times, and yes, yes, yes, Bernd's making this sound again, something between a whimper and a mewl, how awesome is that?!

Marc knows that he has a new goal now, making Bernd Leno mewl and whimper some more, preferably when his rival is pinned down by his own body and impaled on Marc's cock. He's so hard himself, and he's panting against Bernd's neck loudly, his own noises vibrating against Bernd's back. His toes are curling again, and his hand clenched around Bernd's hip will probably leave bruises on the pale skin, but Bernd either doesn't notice the fingers digging painfully into his hipbone, or he doesn't care about it.

The twitching in Marc's hand is getting more and more erratic, and Bernd is tensed like a taut bow, his walls pulsing and clenching around Marc's rock-hard shaft every time he hits the other man's most sensitive spot. Bernd is responding to his fucking so nicely, arching and groaning and _mewling_ like there's no tomorrow, and then he goes stiff and still and comes so hard all over Marc's hand that he can't even catch all of the warm fluid, Bernd's pleasure erupting from his cock in hot spurts like a volcano that has been under pressure for far too long.

Marc strokes and fucks him through his orgasm until Bernd drops down onto the mattress totally exhausted and limp, and Marc muffles his own loud moan on his throat, pumping his painful release into the rubber until his vision goes white for a few seconds. (And no, he's not wishing that he could fill Bernd up and mark him as his without the damn layer of latex between them, absolutely not!)

It goes on for ages, and Marc just remembers in time that crushing Bernd with his weight is not a clever thing to do if he ever wants to hear him whimper again because of his skills as a lover, and he catches himself before he thumps down on the other man, his lips still closed around the spot where Bernd's pulse is still racing, but finally starting to calm down.

It's peaceful and calm, and Marc feels sated and drowsy and happy - until he's rather rudely pulled out of his blissed-out state when Bernd pushes his elbow into his side with surprising force. “Get the fuck off me, ter Stegen!”

Marc wasn't prepared for this, and he's almost kicked out of the bed, but he can just get his balance back before his back makes a painful acquaintance with the floor. Oh, well, he didn't expect a passionate kiss, or even a declaration of Bernd's undying love for him, but this was really uncalled for!

It's not that Bernd fucking Leno didn't quite enjoy himself, right? Because he has, Marc knows that for sure. The proof of Bernd's enjoyment is still sticking mostly to Marc's hand, and he wipes it clean with Bernd's tee, because yeah, if Bernd wants to be a childish dick, then Marc can do the same. He smirks at the heated glare he earns in return, mostly to hide his hurt and his confusion, but also because Bernd's face is still glowing with post-orgasm high when the other man gets up from the bed to stalk over to the bathroom with careful motions.

Marc takes a good look at the glorious ass right before his nose, because, well, he's allowed to look, as this wonderful butt has so totally been his just a few minutes ago, and Marc won't let such an opportunity go to the waste. He throws the used rubber into the trash bin and wipes himself clean – still with Bernd's tee. Their room is warm enough to sleep without clothes, and Marc will happily volunteer as a personal heater for that man after having indulged him and accomplished his mission of teaching Bernd Leno a thorough lesson about his fucking skills.

A lesson he won't forget so soon if the way he's walking is anything to go by with. Marc feels a small sting of a bad conscience at being the reason for Bernd's discomfort, but he'll get used to it with the time, because Marc is so not done with that man yet, definitely not.

He's lying snuggled close under the covers by the time Bernd emerges from the bathroom again, avoiding Marc's eyes. He lies down on his side of the bed, (yes, there is a Marc side and a Bernd side, one of the very few things they don't argue about any longer), pointedly turning his back to Marc.

Marc feels partly amused and partly offended, but it's not like they would hate each other any less just because they have truly fucked for the first time, so this was to be expected.

“Goodnight, Bernd,” he says, curiously waiting for his reaction, and there is a warm rush in his chest when Bernd sighs and relaxes, craning his head to dart a brief look at him. “Night, ter Stegen.”

Marc waits for a moment before he shuffles closer, hesitantly reaching out to wrap his arm around the other man and pull him in. Bernd makes a small sound of protest, but he doesn't move away, and just when Marc is about to fall asleep, Bernd is pulling his arm tightly around himself, interlacing their little fingers over his stomach.

Marc smiles and falls asleep curled against Bernd's back and his glorious ass.


End file.
